High molecular weight esters of C22+ α-olefin derived acids

ABSTRACT

Ester products useful as lubricants for structural resins are obtained by the reaction of mono- and polyfunctional alcohols with high molecular weight branched- and straight-chain aliphatic monocarboxylic acids obtained from α-olefins containing 22 or more carbon atoms. High molecular weight acids useful for the preparation of the present esters are obtained by the free radical addition of a short-chain monocarboxylic acid to the C 22   +  olefin or by ozonization of the C 22   +  olefin. The esters of this invention provide excellent internal-external lubrication for PVC homopolymers and copolymers.

BACKGROUND OF THE INVENTION

To facilitate processing of most resin compositions (e.g.acrylonitrile-butadiene-styrene resins, polystyrene resins, polyamideresins and rigid or plasticized polyvinylchloride (PVC) resins)lubricants are required if useful and uniform finished products are tobe obtained. Lubricants play a particularly important role in theextrusion, injection molding and blow molding of rigid PVC resincompositions.

Both internal and external lubrication is essential to maintainacceptable rheological properties of the melt throughout the processingand to obtain a useful finished product. Internal lubrication operateswithin the melt to reduce the melt viscosity of the polymer at theprocessing temperatures and improve the flow characteristics of thematerials so that a high output of resin is possible using a minimumamount of work and without destroying the physical properties of theresin. External lubrication is required to reduce friction and stickingat the interface between the plastic melt and the metal surfaces ofprocessing equipment in order to obtain a consistently uniform producthaving a smooth finish and essentially free of surface defects.

Emphasis has recently been shifted to developing new and betterlubricant compounds which meet all the lubrication requirements for theprocessing of PVC and other resins, that is, function both as aninternal and external lubricant. U.S. Pat. No. 3,578,621, for example,discloses diesters of the formula ##STR1## wherein R is an alkyl radicalhaving 15 to 30 straight chain carbon atoms and R₁ is an alkylene oralkenylene radical having 2 to 12 straight chain carbon atoms andindicates that these compounds exhibit combined internal and externallubricating properties. Diesters of the above types are prepared byreacting monocarboxylic acids having 16 to 30 carbon atoms arranged in astraight chain with dihydric alcohols having 2 to 12 carbon atoms. Thediesters of the U.S. Pat. No. 3,578,621 are limited to those derivedfrom pure monocarboxylic acids. Diesters obtained from mixed acids(montan wax esters are specifically mentioned) are indicated to beineffective internal-external lubricants in the U.S. Pat. No. 3,578,621.Mixed acids (montanic acids) having a broad molecular weightdistribution are obtained from montan wax and esters thereof arereported in the literature and commercially available. The montanicacids are mixed monocarboxylic acids typically containing from about 22to 36 carbon atoms, with the predominant acids falling in the C₂₆ -C₃₂carbon atom range. The bulk of the monocarboxylic acids derived frommontan wax are straight chain and contain an even number of carbonatoms. These acids are obtained from montan wax by saponification andseparation of the resulting soaps from the unsaponifiable materials.They are also obtainable by the chromic acid oxidation of montan wax.

SUMMARY OF THE INVENTION

We have now discovered novel ester products obtained from high molecularweight synthetic acids derived from α-olefins containing 22 or morecarbon atoms. Quite unexpectedly we have also found that the estersprepared from these high molecular weight synthetic branched- andstraight-chain aliphatic acids exhibit superior internal-externallubrication properties when incorporated into a variety of thermoplasticresins at 0.1 to 5 phr. These esters are particularly useful aslubricants for PVC homopolymer and copolymers.

The esters of this invention are derived from aliphatic hydroxyliccompounds containing 2 to 25 carbon atoms and, more preferably, 2 to 12carbon atoms and 1 to 10 and, more preferably, 2 to 8 primary orsecondary hydroxyl groups and high molecular weight acids obtained bythe ozonization of C₂₂ ₊ α-olefins or by the free radical addition ofshort-chain monocarboxylic acids containing 3 to 12 carbon atoms to C₂₂₊ α-olefins. The mixed acids useful for the preparation of the presentesters which are obtained from the ozonization process contain at least55% by weight C₂₁₋₃₅ acids and fewer than 30% by weight acids havingless than 21 carbon atoms. These mixed acids are further characterizedby having a ratio of odd to even carbn content acids in the C₂₁₋₃₅ rangebetween about 1.5:1 and 10:1 and, more preferably, from 1.75:1 to 4:1.Especially useful esters are obtained with mixed acids containing morethan 70 wt. % C₂₁₋₃₅ acids and less than 20 wt. % acids having fewerthan 21 carbon atoms. Especially useful acids from the free radicaladdition process are obtained when the short chain monocarboxylic acidis propionic acid. Excellent lubricant esters are obtained when thealiphatic hydroxylic compound is ethylene glycol, neopentyl glycol,mono-, di- or tripentaerythritol, or mono-, di-, tri- or tetraglycerol.The preferred lubricant esters typically have acid values less than 30,hydroxyl values less than 40 and melt in the range 50°-120° C.

DETAILED DESCRIPTION

The present invention relates to useful ester compositions derived fromhydroxylic compounds, including mono- and polyfunctional alcohols, andhigh molecular weight aliphatic monocarboxylic acids, which can beeither straight- or branched-chain. The high molecular weightmonocarboxylic acids employed are obtained from alpha-olefins containing22 or more carbon atoms or mixtures of said alpha-olefins (hereinafterreferred to as C₂₂ ₊ α-olefins). Small amounts of olefins containingless than 22 carbon atoms may be present in the olefin mixtures,however, for best results the amount should not exceed 10% by weight ofthe total olefins, and more typically will be less than 5 wt. %. Theremay also be present some internal (non-vinyl) olefins, however, olefinsof the type >C=CH₂ should comprise at least 55% and, more preferably,will be greater than 70 wt. % of the olefin feed.

Alpha-olefins satisfying the above requirements useful for thepreparation of the high molecular weight monocarboxylic acids areobtainable by the polymerization of ethylene. Reactions, referred to aschain growth reactions, where ethylene is added to an aluminum alkyl andinserted between the aluminum and one of the alkyl groups are practicedcommercially and described in the literature. Alpha-olefins ofpredetermined average size are obtained by terminating the growthreaction when the required amount of ethylene has been added and thendisplacing the long alkyl group. The length of the alkyl group will bedependent on the reaction conditions employed and the ethylene charge.Numerous variations of these processes are possible to shift theα-olefin distribution and are within the skill of the art. Where olefinshaving a narrow molecular weight distribution are desired it may benecessary to fractionally distill, solvent extract or otherwise treatthe resulting olefin products prior to conversion of the high molecularweight acids. To obtain the acids from which the esters of thisinvention are derived the olefin will preferably contain 90% by weightor more olefins having 22 or more carbon atoms (C₂₂ ₊ olefins).Excellent results are obtained from ester products derived from olefinscontaining 70% by weight or more olefins having 30 or more carbon atoms(C₃₀ ₊ olefins).

Employing the above-described alpha-olefins, the high molecular weightmonocarboxylic acids used in the preparation of the esters of thisinvention are obtained either (a) by the high-temperature ozonization ofthe olefin or (b) by the free-radical addition of a short-chainmonocarboxylic acid to the olefin. Both these reactions are described inthe literature.

The ozonization of high molecular weight alpha-olefins at elevatedtemperatures is described in the application Ser. No. 361,205 filed May17, 1973, now abandoned and is incorporated herein by reference. In thisprocess high molecular weight olefins or olefin mixtures are contactedwith ozone in a suitable participating reaction medium, preferably at atemperature above the titering point of the olefin/solvent reactionmixture, and then oxidatively cleaved to obtain high molecular weightmonocarboxylic acids. In general the reaction procedure involvesdistinct steps of ozonization followed by scission and oxidation of theformed ozonides.

The first step of the process comprises reacting the olefin or olefinmixture with ozone. It is preferable in carrying out the ozonization tomix the ozone with a carrier gas. Excellent results are obtained whenthe carrier gas is oxygen or a mixture of oxygen with air or carbondioxide and when the gas mixture contains from about 0.1 to about 15% byweight ozone and more preferably from about 1 to 5% ozone. The olefin iscontacted with the ozone in a suitable reactor or absorber to obtain theolefin ozonide. Olefin and solvent may be fed to the reactor separatelyor may be combined in a mixing tank and this mixture charged.

A stoichiometric amount of ozone is generally employed if efficientcontact of olefin and ozone is maintained, however, in certain systems,particularly batch processes, it may be desirable to add a slight excessof ozone to insure that all of the olefin has been converted to ozonide.Participating solvents, which are essential to the safe and efficientconduct of the process, are monocarboxylic acids containing from about 4to about 13 carbon atoms. Pelargonic acid and mixtures of acidscontaining 50% or more pelargonic acid are especially usefulparticipating solvents. In conducting the process the weight ratio ofthe olefin to participating solvent may range from about 2:1 to about1:10 with best results being obtained at weight ratios between about 1:1and 1:3. The olefin and participating solvent may be combined prior tocontacting with the ozone or at least part of the solvent may be addedcontinuously or incrementally at any stage prior to the oxidation andscission step. The temperatures at which the ozonization is conducted isalso important and should be maintained above about 50° C and preferablyabove the titering point of the reaction mixture. Temperatures in theozonization step will therefore usually range between about 60° C andabout 85° C, however, they may go as high as 100° C.

The olefin ozonide formed during the ozonization step is next reactedwith oxygen under conditions which promote scission and oxidation of theozonide to the acid products. The scission and oxidation steps may beconducted simultaneously or as separate and distinct operations. This isachieved in conventional equipment employing either batch or continuousprocedures, the only requirement being that the olefin ozonide beintimately mixed with oxygen and some means provided for temperaturecontrol. The usual temperatures employed in the scission and oxidationsteps of the process range between about 75° and 145° C. If distinctsteps are employed for the scission and oxidation the same temperaturesmay be employed, however, it is more customary to conduct the oxidationat slightly higher temperatures than the scission. Temperatures betweenabout 85° and 105° C are normally employed to cleave the olefin ozonideswhereas it is preferred that the oxidation be conducted at temperaturesbetween about 100° and 125° C. Uniform and controllable scission andoxidation are obtained when these temperature limits are observed.

An amount of gaseous oxygen sufficient to completely oxidize the ozonideis required. While pure oxygen may be advantageously employed otheroxygen-containing gases such as mixtures of oxygen with argon, helium,neon or nitrogen may also be used for this purpose, however, the gasmixtures should contain at least 20% by weight oxygen. An amount ofoxygen ranging from about 1 to about 4 moles of oxygen per mole ofolefin is used but larger amounts may be employed, as desired, to speedthe process, insure complete oxidation and improve yields. Theefficiency of contacting the materials is important since the timerequired for splitting and oxidizing the ozonides is highly dependentthereon. In most instances this phase of the reaction is substantiallycomplete in from about 1/2 to about 20 hours.

Catalysts are not necessary to bring about the scission and oxidation ofthe ozonide, however, they are usually desirable to accelerate thesereactions. Synergistic combinations of catalytic agents may be used.Useful materials which may be added to the ozonide mixture prior tosubjecting it to oxidation and which serve as catalytic agents includethe alkali and alkaline earth metal hydroxides and various metalcompounds including salts of Group VIII metals, preferably, iron, cobaltand nickel, and other compounds of these and other metals such asmanganese. The chlorides, sulfates and carboxylates of these metals areuseful as are the oxides and hydroxides. The metal compounds may be usedindividually or combinations of two or more metal compounds may beuseful. The amount of the total catalyst will range from about 0.01 toabout 2% by weight of the total reaction mixture.

Employing olefin feeds as described above in the ozonization process theresulting straight-chain mixed acids will generally contain less than 30weight percent acids having fewer than 21 carbon atoms. The bulk of themixed acids contain 21 or more carbon atoms with C₂₁₋₃₅ acidsconstituting 55% by weight or more of the mixed monocarboxylic acidproduct with less than 20% by weight acids having greater than about 35carbon atoms. Most often, particularly when C₃₀ ₊ olefins are employed,the acid compositions will contain less than about 20 weight percentacids having fewer than 21 carbon atoms, greater than 70 weight percentC₂₁₋₃₅ acids and less than about 10% acids containing more than 35carbon atoms. The ratio of odd carbon content acids to even carboncontent acids in the C₂₁₋₃₅ range is between 1.5:1 and 10:1. This ratiois more generally from about 1.75:1 to about 4:1. The distribution ofmonocarboxylic acids and the ratio of the odd to even carbon contentacids distinguishes the present products obtained from α-olefins fromthose derived from montan wax acids.

In addition to the high molecular weight acids obtained from theabove-described ozonization process of C₂₂ ₊ olefins, which arepredominantly straight-chain acids, branched-chain high molecular weightacids obtained by the free radical addition of short-chainmonocarboxylic acids to the C₂₂ ₊ olefin are also useful for theproduction of the novel and useful esters of this invention. Acidsobtained by such free radical addition reactions are predominantlyα-alkyl monocarboxylic acids containing at least 25 carbon atoms.Processes for preparing such high molecular weight branched-chain acidsare described in the prior art in British Pat. Nos. 960,894, 1,098,464and 1,098,465, U.S. Pat. No. 2,823,216 as well as in other references.The α-olefin is reacted with a short-chain monocarboxylic acidcontaining 3 to 12 carbon atoms such as propionic, butyric, valeric,2-ethylhexoic, pelargonic or lauric acids using a suitable free radicalgenerating means. Excellent results are obtained with the addition ofpropionic acid to the α-olefin using free radical initiators such asinorganic and organic peroxides, persulfates, perborates andperchlorates. In addition to the 1:1 addition product, i.e. the α-alkylmonocarboxylic acids, other adducts are possible from the free radicalreaction depending on the reactant ratio and the reaction conditions.For example, 2:1 (olefin:acid) adducts, α,α'-dialkyl monocarboxylicacids, can be obtained. Similarly, some 1:2 adduct may also be formedduring the reaction. It is also possible under the free radicalconditions of this reaction to form dimers and possibly higher oligomersof the olefin which in turn can react with short-chain acid to yieldproducts having approximately double the molecular weight. For example,a C₂₂ α-olefin could form a C₄₄ α-olefin which in turn could react withpropionic acid to yield a C₄₇ α-methyl branched acid. While the 1:1adducts are the predominant species under normal reaction conditions,substantial amounts of these other adducts can be formed and are notdetrimental to the formation of the esters of this invention.

The esters of this invention are prepared employing either of theforegoing types of high molecular weight monocarboxylic acids derivedfrom C₂₂ ₊ olefins. Esters obtained with these acids are extremelyuseful lubricants for structural resins, particularly PVC homopolymerand copolymer resins. These esters have the ability to function as bothinternal and external lubricants and satisfy the total lubricant needsof the resin so that the incorporation of other lubricant additives isnot required. The superior performance characteristics are mostsurprising when it is considered that similar esters obtained withnaturally occurring mixed acids, such as esters of montanic acids, donot exhibit the same high degree of internal-external lubrication as theesters of this invention.

In addition to the unexpectedly superior internal-external lubrication,the fact that these products are readily obtainable from completelysynthetic sources, thus insuring uniformity or, where desired,controlled variation of the composition, makes these esters commerciallyattractive. The present compositions also have other useful propertieswhich contribute to their effectiveness and desirability as lubricants.For example, the present ester products are readily dispersible in andcompatible with a wide variety of resins. These esters also havesuperior heat stabilities and are capable of withstanding rigorousprocessing for prolonged periods without significant decomposition, thusinsuring minimal discoloration and loss of physical properties in thefinished product. The esters have high melting points which isconsidered useful in maintaining a lubricating film. The high molecularweight of these compositions also makes them resistant to volatilizationduring the processing operations. In addition to all of theabove-mentioned features these esters can be utilized at very low levelsresulting in considerable economic advantage to the user. This featurealso minimizes the plasticization effect of the lubricant additive onthe resin.

The esters of this invention are obtained by the reaction of thealpha-olefin derived high molecular weight monocarboxylic acids and analiphatic hydroxylic compound containing from 2 to about 25 carbon atomsand from 1 to about 10 primary or secondary hydroxyl groups. Usefulaliphatic hydroxylic compounds include monohydric alcohols, di- andhigher polyhydric alcohols and ether alcohols, which can be either mono-or polyfunctional. By way of illustration useful aliphatic monohydricalcohols include ethanol, n-propanol, sec-propanol, n-butanol,t-butanol, isoamyl alcohol, n-hexanol, 2-ethylhexanol, n-octanol,isodecanol, capryl alcohol, lauryl alcohol, myristyl alcohol, cetylalcohol, stearyl alcohol and oxo alcohols such as tridecyl alcohol,which is mainly tetremethyl-1-nonanol, and hexadecyl alcohol which is acomplex mixture of primary alcohols characterized as 2,2-dialkylethanols where the alkyl groups are predominantly methyl-branched C₆ andC₈ radicals. Useful aliphatic polyols for the preparation of the estersof this invention include ethylene glycol, 1,2-propylene glycol,1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol,1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,3-dimethyl-2,3-butanediol,trimethylol propane, mannitol, sorbitol, glycerol, pentaerythritol andthe like. Ether alcohols (intermolecular ethers formed by thecondensation of two or more molecules of a polyol accompanied by theelimination of water) are also useful for the preparation of the estersof this invention. The ether alcohols can be either mono- orpolyfunctional and contain from 2 up to as many as 8 condensed polyolunits. Illustrative ether alcohols which can be employed are diethyleneglycol, triethylene glycol, tetraethylene glycol, diethylene glycolmonomethylether, diethylene glycol monoethylether, triethylene glycolmonomethyl ether, butoxyethanol, butylene glycol monobutylether,dipentaerythritol, tripentaerythritol, tetrapentaerythritol, diglycerol,triglycerol, tetraglycerol, pentaglycerol, hexaglycerol, heptaglycerol,octaglycerol and the like. When polyols and ether polyols are employedit is not necessary that all the available hydroxyl groups be reactedwith the high molecular weight monocarboxylic acids. As will berecognized by those skilled in the art, partial ester are possible usingpolyols and are within the scope of this invention. It is advantageous,however, when employing a polyol or mixture of polyols to convert atleast 50% of the available hydroxyl groups to esters.

Superior ester products useful as lubricants for resins are obtainedwith aliphatic polyols and ether polyols containing from about 2 to 12carbon atoms and 2 to 8 primary or secondary hydroxyl groups.Exceptionally useful ester lubricants possessing excellentinternal-external lubrication properties are obtained when the polyolsare ethylene glycol, neopentyl glycol, pentaerythritol,dipentaerythritol, tripentaerythritol, glycerine, and di-, tri- andtetraglycerol. These preferred ester compositions will generally meltbetween about 50° and 120° C and have acid values less than 30 andhydroxyl values less than 40.

The reaction of the high molecular weight monocarboxylic acid and thealiphatic hydroxylic compound is carried out using conventionalesterification procedures and equipment, that is, by heating thereaction mixture with or without a catalyst at a temperature from about100° to 300° C while removing the water of reaction. The esterificationreactions are more usually conducted within the temperature range 150°to 250° C. It is not essential but a catalyst can be used. Acidcatalysts such as sulfuric acid, phosphoric acid, alkyl and arylsulfonic acids such as p-toluene sulfonic acid and methane sulfonicacid, and a variety of metal compounds including dibutyl tinoxide,tetrabutyl titanate, zinc acetate, stannous oxalate, iron oxide, ferricstearate, manganous stearate, cobaltous stearate, and the like areillustrative of the numerous compounds capable of catalyzing thereaction. The amount of catalyst will usually range from 0.1 to 1.0% byweight of the total reactant charge. A diluent which is inert to thereaction conditions and which forms and azeotrope with water, such asbenzene, toluene or xylene, can be employed in carrying out the reactionbut is not necessary. Stiochiometric amounts of the acid and alcoholwill usually be employed, however, with the lower boiling hydroxyliccompounds an excess of an alcohol can be charged. The excess hydroxyliccompound is distilled from the reaction mixture as the esterificationreaction is carried to completion and may be recycled, if desired.Usually up to about 25 wt. % excess of the hydroxylic compound willsuffice for this purpose, however, larger amounts can be used. While theesterification reaction may be conducted entirely at atmosphericpressure it is generally more desirable to reduce the pressure to about2-50 mm Hg. during the final stages to remove the last traces of waterand strip off excess glycol or other volatiles which may be present. Theesters are generally used as they are obtained from such reactions andrequire no additional treatment, however, if improvement in the color ofthe ester is desired it can be bleached with ozone, peroxide,hypochlorite or other suitable bleaching agents or decolorized usingbleaching clays, charcoal or the like.

Esters obtained in accordance with this invention exhibit superiorinternal and external lubrication when used with a variety ofthermoplastic resins. While these esters are particularly useful withpolyvinylchloride homopolymers and copolymers, they also findapplication with acrylonitrilebutadiene-styrene copolymers,polyacrylonitrile, polystyrene, polybutadiene, polyesters, polyolefins,polyvinylbutyral, cellulose acetate and the like. These esters also haveapplication with post-chlorinated polyvinylchloride. Usefulpolyvinylchloride copolymers include those obtained when vinyl chlorideis polymerized with vinyl acetate, vinyl bromide, vinyl propionate,vinyl butyrate, vinylidene chloride, methylmethacrylate, methylacrylate,2-ethylhexylacrylate, acrylonitrile, methacrylonitrile, styrene and thelike, or any combination of two or more of these comonomers. The presentesters are especially useful with polyvinylchloride resins having vinylchloride contents above about 50 percent by weight. The amount of esteremployed will vary between about 0.1 part and about 5 parts per 100parts by weight of the resin, however, the esters more usually rangebetween about 0.2 and 2 phr.

The esters of this invention are readily compatible with theaforementioned resins within the limits required for efficientinternal-external lubrication. They can be incorporated into PVC orother resins using conventional means such as blending on a mill ormixing in a Banbury mixer or other internal mixer or kneading apparatus.The ester can be dissolved or dispersed in a suitable solvent and addedto the resin in this manner. The lubricants can be added separately orincluded in a masterbatch with other compounding ingredients. Thepresent esters are readily compatible with the other compoundingingredients such as stabilizers (to protect the resins against thedeleterious affects of oxygen, heat and light), pigments, dyes, fillers,plasticizers, processing aids, and the like, and can be used inconjunction therewith to provide formulated resins having a good balanceof physical properties. The physical properties of the formulated resincan be varied widely by manipulation of the amount and type ofcompounding ingredients without appreciably detracting from theinternal-external lubrication properties of the ester.

The following examples illustrate the present invention more fully,however, they are not intended as a limitation on the scope thereof. Inthese examples all parts and percentages are given on a weight basisunless otherwise indicated.

EXAMPLE I

To obtain the mixed acid products useful in the preparation of theesters of this invention equal parts of C₃₀ ₊ α-olefin (Gulf C₃₀ ₊olefin fraction, m.p. 160°-167° F, containing 78 wt. % C₃₀ and higherolefins) and pelargonic acid were fed into the top section of acountercurrent absorber while a stream of oxygen and carbon dioxidecontaining approximately 1.5-2% ozone was fed into the bottom section.The rates of flow of the O₃ /O₂ gas stream and the olefin feed wereadjusted so that the C₃₀ ₊ α-olefin absorbed as much ozone as possiblein passing through the absorber and so that all but trace amounts ofozone were removed from the oxygen. The temperature in the absorber wasmaintained in the range 65°-85° C. The effluent gases were scrubbed withwater to remove organic vapors and particulate matter and then passedthrough a catalytic furnace where organic matter was oxidized to carbondioxide and water. The gas was then dried and recycled.

The ozonide was removed from the bottom of the absorber and passed intoa decomposition vessel containing a heel of pelargonic acid, 0.25%sodium hydroxide based on weight of ozonide and previously decomposedozonide to serve as a diluent. The decomposition vessel was maintainedat a temperature of 95° C while adding oxygen containing 1% ozone andthe ozonide added over a 2 hour period. When the addition was completethe decomposition was continued for 2 additional hours beforetransferring to an oxidation reactor. The oxidation was carried out inthe presence of manganese acetate tetrahydrate (0.1% based on the C₃₀ ₊olefin) in an oxygen atmosphere. The time required for oxidation was 4hours.

The mixed oxidation product was then stirred with 0.5% phosphoric acid(75%) for 15 minutes and an activated bleaching clay (Filtrol GradeNo. 1) added with additional stirring. The mass was filtered to removethe manganese salts of phosphoric acid and the filter aid and thenstripped of pelargonic acid under reduced pressure using a Vigreauxcolumn. The stripping was conducted at 230° C and during the finalstages the pressure was reduced to 0.5 torr. A portion of the mixed acidproduct, crystallized from glacial acetic acid, was analyzed bygas-liquid chromatography of the methyl esters employing a modificationof ASTM Test Method D 1983-64T. A Hewlett Packard Model 7550chromatograph equipped with a 6 foot × 1/8 inch stainless steel columnpacked with 10% silicone rubber on 80-100 mesh Diatoport S was used. Theinstrument was programmed for an 8° C per minute temperature rise overthe range 75°-333° C with a helium flow of 15 mls per minute and 50psig. The mixed acid product (equivalent weight 586; 7-8 Gardner color)had the following compositional analysis:

    ______________________________________                                               Acid          Wt. %                                                    ______________________________________                                               C.sub.9.sub.-21                                                                             10.27                                                           C.sub.22      3.85                                                            C.sub.23      5.14                                                            C.sub.24      3.26                                                            C.sub.25      6.83                                                            C.sub.26      3.08                                                            C.sub.27      11.57                                                           C.sub.28      2.83                                                            C.sub.29      12.54                                                           C.sub.30      1.72                                                            C.sub.31      10.53                                                           C.sub.32      1.29                                                            C.sub.33      8.13                                                            C.sub.34      0.89                                                            C.sub.35      6.00                                                            C.sub.36 +    11.95                                                                         99.88                                                    ______________________________________                                    

EXAMPLE II

A predominantly alpha-methyl branched high molecular weightmonocarboxylic acid was prepared by charging a glass reactor with 200grams of an alpha-olefin mixture containing greater than 85 wt. % C₂₂₋₂₈olefins (Gulf C₂₂ ₊ alpha-olefin fraction, m.p. 127° F), 326 gramspropionic acid and 8 grams di-t-butyl peroxide. The system was flushedwith nitrogen and a slight nitrogen flow maintained while the reactionmixture was heated at reflux for about 4 hours. At the completion of thereaction unreacted propionic acid was removed under vacuum at 200° C.225 Grams of the C₂₅ ₊ alpha-methyl monocarboxylic acid having an acidvalue of 48 was recovered.

EXAMPLE III

A reactor was charged with a mixture of 300 grams of the C₂₂ ₊ olefin ofExample II and 200 grams pelargonic acid (Emfac 1202 pelargonic acid). Astream of oxygen containing 3% ozone was continuously bubbled in belowthe surface of the liquid at a rate of 24 SCFH at 4 psig so thatapproximately 35 grams ozone was being charged per hour. The temperatureof the absorber was maintained above the titering point of the reactionmixture with vigorous agitation to insure intimate contact with theozone and the progress of the reaction followed by analyzing theoff-gases. Ozonolysis was terminated when ozone absorption dropped below15%. The ozonides were oxidatively cleaved by the dropwise addition ofthe ozonide mixture into a vessel containing 100 grams pelargonic acidand 0.75 grams sodium hydroxide over a period of about 90 minutes. Thereaction mixture was vigorously agitated and maintained at about 95° Cwhile bubbling in a stream of oxygen containing 1% ozone at a rate of2.4 SCFH. When the addition was complete, stirring was continued for anadditional 90 minutes while bubbling in the O₃ /O₂ mixture. The ozonegenerator was then turned off. Manganese acetate tetrahydrate (1.5 gms)was added and the temperature of the reaction mixture raised to 120° Cwhile bubbling in pure oxygen with stirring. After 31/2 hours theoxidation reaction was complete and the mixed oxidation was stripped ofpelargonic acid by heating to 245° C while pulling a vacuum of 25 torron the system. The mixed acid product contained approximately 80 wt. %C₂₁ ₊ monocarboxylic acids.

EXAMPLE IV

234 Grams of an α-methyl branched monocarboxylic acid (acid value 60)obtained by the addition of propionic acid to a C₃₀ ₊ α-olefin(approximately 75 wt. % C₃₀ and higher olefins) was charged to a glassesterification vessel with 100 mls decanol. The reaction mixture washeated to 270° C under nitrogen for several hours until 4 mls of waterwas removed. Excess decanol was then stripped from the reaction mixture.The resulting ester product had an acid value (AV) of 4.1, hydroxylvalue of 35 and melted in the range 67°-75° C.

EXAMPLE V

Employing a similar procedure, 8 grams ethylene glycol (0.125 mole), 234grams of the α-methyl monocarboxylic acid of Example IV (0.25 mole) and1.2 grams NaH₂ PO₂ catalyst were charged and reacted at 245° C for about3 hours. The ester product, obtained after filtering with diatomaceousearth, had an AV of 18.4, hydroxyl value of 11.2 and melt point of69°-72° C.

EXAMPLE VI

Using conventional esterification procedures, 100 grams of a mixedC₁₀₋₁₂ linear alcohols (average molecular weight 163) and 351 grams ofthe α-methyl monocarboxylic acid of Example IV were reacted. NaH₂ PO₂was employed as the catalyst. The reaction was conducted at 235° C undernitrogen for 4 hours during which time 5.5 mls of water was removed. Thereaction mixture was then stripped at 220° C under reduced pressure (3mm Hg) to remove the excess alcohol and filtered through Dicalite. Theresulting ester product had an acid value of 5.3, a hydroxyl value of15.7 and melted at 65°-66° C.

EXAMPLE VII

In a similar manner ethylene glycol was esterified with a mixed acidobtained by ozonolysis of a C₃₀ ₊ α-olefin as described in Example I.200 Grams of the mixed acid (acid value 82; neutral equivalent 685) and9 grams ethylene glycol were reacted at 245° C under a nitrogenatmosphere employing 0.5 grams NaH₂ PO₂ catalyst. After approximately 5mls of water was removed, the reaction mixture was stripped and bleachedwith Filtrol for about 1/2 hour at 90° C under nitrogen. The final esterproduct had an acid value of 12.5, hydroxyl value of 39 and melted at75°-77° C.

EXAMPLE VIII

Employing 115 grams of the mixed acid of Example VII and 90 grams of aC₂₀ ₊ alcohols with 0.5 wt. % catalyst, an ester having an acid value of5.1, hydroxyl value of 28 and melting in the range 42°-50° C wasobtained.

EXAMPLE IX

115 Grams of a C₂₉ ₊ monocarboxylic acid mixture (AV 97.5) obtained bythe ozonolysis of a C₃₀ ₊ olefin mixture was reacted with 6 gramsglycerine using 1 gram NaH₂ PO₂ catalyst. The ester product, obtainedafter filtration with Dicalite, melted at 68°-71° C, had an acid valueof 1.3 and hydroxyl value of 53.

EXAMPLE X

To demonstrate the ability of the ester products of Example IV-IX tofunction as lubricants for PVC the esters were incorporated in thefollowing standard pipe formulation:

    ______________________________________                                        PVC resin (Geon 101-EP)                                                                            100      parts                                           Tin mercaptide stabilizer                                                                          2        parts                                           Acrylic processing aid                                                                             4        parts                                           Titanium dioxide     3        parts                                           Ester lubricant      0.5-1    part                                            ______________________________________                                    

The ingredients were blended in Henschel high speed mixer and the resinevaluated in a Brabender plasticorder -- a convenient laboratoryevaluation tool which measures the flow properties of the resin againsttime. Fusion times were determined on a 51 gram sample using a No. 6roller head at 30 rpm and 195° C. Test results were as follows:

    ______________________________________                                                        Lubricant                                                                     Level     Fusion Time                                         Ester of Example:                                                                             (phr)      (minutes)                                          ______________________________________                                        IV              0.5        >60                                                V               0.5          64.5                                             VI              1          >50                                                VII             1            50                                               VIII            1          >60                                                IX              1            60                                               Control         0          ˜1                                           (no lubricant)                                                                ______________________________________                                    

It is evident from the above data that the esters of this invention areeffective lubricants for PVC and appreciably extend the fusion time ofthe formulated resin.

EXAMPLE XI

The glycerine and tripentaerythritol esters of mixed C₂₉ ₊monocarboxylic acids obtained by the ozonization of an α-olefin mixturecontaining 75% by weight or more olefins having 30 or more carbon atomswere prepared and are hereinafter referred to as esters XIA and XIB,respectively. The esterification reaction was carried out in the usualmanner employing 0.3 wt. % H₃ PO₂ and 0.3 wt. % butyl titanatecatalysts. The esters had the following properties:

    ______________________________________                                        Ester Product                                                                           Acid Value                                                                              Hydroxyl Value                                                                            Melt Point (° C)                       ______________________________________                                        XIA       14.1      20.2        59-64                                         XIB       19.3      37          71-75                                         ______________________________________                                    

These two esters were blended with polyvinylchloride resin (DiamondShamrock PVC-40; inherent viscosity 0.83) at a 0.5 phr level inaccordance with the following recipe:

    ______________________________________                                        PVC resin             100     parts                                           Tin mercaptide stabilizer                                                                           2       parts                                           Epoxidized soya       1       part                                            ______________________________________                                    

Pressed 10 mil sheets of these resins exhibited excellent clarity. 56Gram samples of each of the formulated resins were evaluated employingfusion conditions with the Brabender plasticorder at a temperature of160° C using a No. 6 roller head and rotor speed of 60 rpm. Fusion dataobtained for the resins lubricated with esters XIA and XIB and anunlubricated control resin were as follows:

    __________________________________________________________________________           T.sub.s         T.sub.p                                                       (Time to start                                                                        Torque  (Time to                                                                             Torque                                          Ester Lube                                                                           of fusion)                                                                            (meter grams)                                                                         fusion peak)                                                                         (meter grams)                                   __________________________________________________________________________    XIA    9'30"   850     16'15" 3250                                            XIB    >60'    350     >60'    350                                            Control                                                                              2'18"   1640    5'45"  4150                                            __________________________________________________________________________

The extended fusion time of the formulated resins showed the esters ofthis invention to be highly efficient lubricants for PVC. The data alsoindicates that a significant reduction in the use level of the esterlubricant is possible in the compounding of the resin.

The resin formulations were also evaluated for dynamic thermal stabilityin the Brabender at a temperature of 195° C (other test conditionsremained unchanged) with the following results:

    ______________________________________                                                T.sub.i             T.sub.tg                                                  (Time of initial    (Time to thermal                                  Ester Lube                                                                            torque rise)                                                                              Torque  degradation peak)                                                                        Torque                                 ______________________________________                                        XIA     15'00"      1850    18'00"     2750                                   XIB     17'15"      1850    21'30"     2750                                   Unlubrica-                                                                             9'00"      2150    12'24"     3400                                   ted Control                                                                   ______________________________________                                    

It is apparent from this data that the stability of the formulated resinis enhanced by the addition of the ester products of this invention.

EXAMPLE XII

Esters XIA and XIB were employed in the following PVC formulation:

    ______________________________________                                        PVC (Diamond Shamrock PVC-40)                                                                       100     parts                                           Acrylic Processing Aid                                                                              4       parts                                           Tin mercaptide stabilizer                                                                           2       parts                                           Epoxidized soya       1       part                                            Lubricant ester       0.5     part                                            ______________________________________                                    

The formulated resins were extruded employing the Brabender machinefitted with an extrusion head model EX-200. The extrusion was carriedout at a screw speed of 40 rpm (3/4 inch diameter -- 20:1 L/D -- 4:1compression ratio screw; 1/4 inch diameter rod die). The temperature ofthe first zone was 350° F. The second zone was heated to 365° F and dietemperature was 380° F. Extrusion results were as follows:

    ______________________________________                                                                         Die pressure                                 Ester Lube                                                                              Rate (lbs/hr) Torque   (psig)                                       ______________________________________                                        XIA       4.8           2300     1250                                         XIB       5.1           1500      900                                         Unlubricated                                                                            3.1           4800     2800                                         Control                                                                       ______________________________________                                    

EXAMPLE XIII

The tripentaerythritol ester (XIB) was blended into a vinylchloride/vinyl acetate (97/3) copolymer at a 0.5 phr level with 2 phrtin mercaptide stabilizer and 2 phr epoxidized soya. The dynamic thermalstability of this resin was measured with the Barbender plasticorder asdescribed in Example XI. T_(i) was 17'15" at a torque of 1900 metergrams. T_(tg) was 33'00" at a torque of 2750 meter grams.

EXAMPLE XIV

An ester was prepared employing conventional procedures and a H₃ PO₂/butyl titanate catalyst system by reacting 1 mole pentaerythritol and 4moles crude mixed acids containing greater than 70 wt. % C₂₁₋₃₅ acidswherein the ratio of odd to even carbon content acids in the C₂₁₋₃₅range was about 3:1 obtained from the ozonization of a C₃₀ ₊ α-olefin.The esterification was carried out at 215°-228° C. The ester product,obtained after filtration with 1% Dicalite, had an acid value of 16.7,hydroxyl value of 17.9 and melted at 60°-65° C. This ester was blendedin the folloing rigid PVC bottle formulation:

    ______________________________________                                        PVC resin (Ethyl SM-200)                                                                           100     parts                                            Tin stabilizer       2       parts                                            Acrylic processing aid                                                                             3       parts                                            Impact modifier      12      parts                                            Lubricant ester      1       part                                             ______________________________________                                    

When the resin formulation was evaluated in the Brabender machine (177°C at 50 rpm) to determine its fusion properties, it was observed thatthe fusion time was more than double that of the resin formulationcontaining all the compounding ingredients except the lubricant ester.

EXAMPLE XV

A triglycerol ester (XVA) and tetraglycerol ester (XVB) were preparedemploying stoichiometric amounts of predominantly C₂₁₋₃₅ aliphaticmonocarboxylic acids and the polyols. The triglycerol ester had an acidvalue of 17.8, hydroxyl value of 35 and melted at 70°-75° C. Thetetraglycerol ester had an acid value of 26.6, hydroxyl value of 29.5and melted in the range of 75°-80° C. Both these esters were employed at0.5 phr level in the formulation of Example XII and the fusionproperties determined with the following results:

    ______________________________________                                        Ester Lubricant                                                                            T.sub.s   Torque   T.sub.p                                                                              Torque                                 ______________________________________                                        XVA          7'30"     750      11'45" 2950                                   XVB          15'15"    750      20'12" 3000                                   Unlubricated 1'24"     1900      3'30" 4100                                   Control                                                                       ______________________________________                                    

EXAMPLE XVI

788 Parts of the α-methyl branched acid of Example II and 25 partsethylene glycol were charged to an esterification reactor with 0.3 wt. %H₃ PO₂ and 0.3 wt. % butyl titanate catalyst. The reaction mixture washeated to about 235° C for about 3 hours during which time the acidvalue decreased to 28.0. Additional catalyst was then charged to thereactor with about 5 parts ethylene glycol and the reaction continued at235° C for 4 hours. The final ester product (acid value of 23.6 and meltpoint 63°-65° C) was evaluated for dynamic thermal stability in PVCcopolymer (97 wt % vinyl chloride/3 wt. % vinyl acetate) at 0.5 phrlevel. The formulation also included 2 phr tin stabilizer and 2 phrepoxidized soya. The formulated resin had a T_(i) of 17'15" at 1900meter grams torque and T_(tg) of 33'00" and 2750 meter grams torque ascompared to an unlubricated control which had a T_(i) or 11'30" at 2100meter grams torque and T_(tg) of 17'24" at 3450 meter grams torque.

EXAMPLE XVII

In an effort to make a direct comparison of the tripentaerythritol esterof Example XI and a tripentaerythritol ester obtained using montan waxacids, the following experiment was conducted. Stoichiometric amounts oftripentaerythritol and montan wax acids (1 mole polyol:8 moles mixedacids) were charged to an esterification reactor with a conventionalcatalyst system. The montan wax acids were a commercially availablematerial (Hoechst LP) which has an acid value in the range 115-130 and adrop point (modified ASTM D 556-49) in the range 78°-83° C. Analysis ofthe montan wax acids using the procedure described in Example Iindicated that approximately 94% by weight of the acids were C₂₁₋₃₅acids and about 3.5% by weight acids contained less than 21 carbonatoms. The ratio of odd to even carbon content in the C₂₁₋₃₅ range was0.42:1. The esterification was conducted in the usual manner at225°-230° C and the reaction followed by reduction in acid value. After4 hours the acid value was only 45. When an effort was made to furtherreduce the acid value by additional heating the reaction mixture gelled.In an effort to eliminate gellation the reaction was repeated using thesame reactants and catalyst but about 20% excess of the montan wax acidswere charged. An acid value of 43 was obtained in 21/2 hours, however,the product gelled before the acid value could be reduced below 40.

EXAMPLE XVIII

An ester of ethylene glycol and mixed high molecular weight acids(designed as Ester A) obtained by the ozonolysis of a C₃₀ ₊ α-olefin wasprepared for direct comparison against a commercially available waxester (Hoechst E) produced from ethylene glycol and montan wax acids.The commercial wax ester had an acid value of 15-20 and drop point(modified ASTM D 556-49) of 76-81 and is designated as Ester B. The highmolecular weight mixed acids used in the preparation of the estercontained about 10% C₉₋₂₁ acids, about 12% acids having more than 35carbon atoms and about 88% C₂₁₋₃₅ acids, with the ratio of odd to evencarbon content acids in the C₂₁₋₃₅ range being about 2:1. Ester A had anacid value of 19, hydroxyl value of 26 and melted in the range 75°-82°C.

The two ester products were incorporated into a PVC homopolymer inaccordance with the following recipe:

    ______________________________________                                        PVC resin (Diamond Shamrock PVC-40)                                                                    100     parts                                        Octyl tin stabilizer     2       parts                                        Epoxidized soya          1       part                                         Lubricant ester          0.5     part                                         ______________________________________                                    

The formulated resins were milled on a conventional two roll mill at350° F and sheeted out. Sheets were then pressed to 10 mil thickness ina 6 × 8 × 0.010 inch mold at 360° F and 500 psig for 3 minutes and 200psig for 5 minutes. Pressed sheets containing Esters A and B bothexhibited excellent clarity. 1 × 1 inch Squares were then stamped fromthe sheets and arranged on a series of eight glass trays which werefitted in a rotating ferris-wheel type device in an electric ovenmaintained at 380° F. Samples were removed from the oven at 10 minuteinvervals, allowed to cool and observed for discoloration and othersigns of polymer degradation. The testing was terminated when all thesamples failed or after 80 minutes. The resin formulation containingEster A exhibited the first color change after 40 minutes whereas theresin formulation containing Ester B showed first signs of discolorationafter 30 minutes. The resin containing Ester B was completely degradedwithin 70 minutes while the resin lubricated with Ester A withstood thecomplete 80 minute cycle before degradation.

Fusion data and dynamic thermal stability data were also obtained forthe formulated resins in accordance with the procedure of Example XIIand are recorded below:

    ______________________________________                                        FUSION DATA                                                                   ______________________________________                                        Lubricant T.sub.s    Torque    T.sub.p Torque                                 ______________________________________                                        Ester A   9'30"       950      14'45"  2700                                   Ester B   7'15"      1000      10'00"  3450                                   None      2'18"      1650       5'45"  4150                                   ______________________________________                                    

    ______________________________________                                        DYNAMIC THERMALSTABILITY DATA                                                 ______________________________________                                        Lubricant T.sub.i    Torque    T.sub.tg                                                                              Torque                                 ______________________________________                                        Ester A   25'00"     1600      31'00"  2700                                   Ester B   14'30"     1800      17'30"  2750                                   None       9'00"     2150      12'24   3400                                   ______________________________________                                    

The commercial wax ester (B) and the ethylene glycol ester prepared inaccordance with this invention (A) were also evaluated for their abilityto be extruded employing the formulation and procedure described inExample XII. The following extrusion data was obtained:

    ______________________________________                                                  Rate                 Die Pressure                                   Lubricant (lbs/hr)   Torque    (psig)                                         ______________________________________                                        Ester A   4.5        2400      1250                                           Ester B   4.7        3300      1250                                           None      3.1        4800      2800                                           ______________________________________                                    

It is evident from the above Examples and comparative data that superiorester products are obtained by utilizing the high molecular weight acidsderived from C₂₂ ₊ α-olefins. It is also clearly shown that these esterproducts are efficient lubricants for thermoplastic resins, particularlyfor PVC homopolymers and copolymers, and that the esters of thisinvention are more effective than similar ester compositions derivedfrom high molecular weight acids obtained from natural sources, such asmontan wax acids.

In addition to their ability to function to lubricants for thermoplasticresins the esters of this invention also have other applications.Typically, they find use in any application where known wax esters,either synthetic or natural, have been utilized. For example, the estersof this invention are useful flip and antiblock agents. They can also beutilized in a wide variety of polishes including shoe polish, floorpolish and automotive polishes. To demonstrate this latter point, 4.5parts of ester A of Example XI was melted at 110° C with 1.5 partsmicrocrystalline wax (Petrolite C-1035), 3 parts carnauba was (NC No.3), 21 parts paraffin wax (m.p. 143° F) and a solution (50° C) of 70parts turpentine and 3 parts black dye was added to the melt, blended,cooled with stirring to 42° C and poured into containers. The resultingwax composition was an excellent polish for shoes and gave a high lustreshine. The product also had good surface gloss and solvent retention.

We claim:
 1. An ester derived from an aliphatic hydroxylic compoundhaving 2 to 25 carbon atoms and 1 to 10 primary or secondary hydroxylgroups and a mixed straight-chain aliphatic monocarboxylic acid obtainedby the ozonization of a C₂₂ ₊ α-olefin wherein at least 90% by weight ofthe olefins contain 22 or more carbon atoms, said mixed acid containingless than 30% by weight acids having fewer than 21 carbon atoms, lessthan 20% by weight acids having greater than 35 carbon atoms and 55% byweight or more C₂₁₋₃₅ acids with the weight ratio of odd to even carboncontent acids in the C₂₁₋₃₅ range being between 1.5:1 and 10:1.
 2. Theester of claim 1 wherein the mixed straight-chain aliphaticmonocarboxylic acid is derived from an α-olefin wherein 70% by weight ofthe olefins contain 30 or more carbon atoms.
 3. The ester of claim 1wherein the aliphatic hydroxylic compound is an aliphatic polyol orether polyol having from 2 to 12 carbon atoms and 2 to 8 primary orsecondary hydroxyl groups.
 4. The ester of claim 3 which is furthercharacterized by having an acid value less than 30, a hydroxyl valueless than 40 and a melt point between about 50° and 120° C.
 5. The esterof claim 3 wherein the mixed straight-chain aliphatic monocarboxylicacid contains less than 20 weight percent acids having fewer than 21carbon atoms, less than about 10 weight percent acids having more than35 carbon atoms and greater than 70 weight percent C₂₁₋₃₅ acids with theratio of odd to even carbon content acids in the C₂₁₋₃₅ range beingbetween 1.75:1 and 4:1.
 6. The ester of claim 5 wherein the aliphatichydroxylic compound is selected from the group consisting of ethyleneglycol, neopentyl glycol, pentaerythritol, dipentaerythritol,tripentaerythritol, glycerol, diglycerol, triglycerol or tetraglycerol.